Kitfox Aircraft Stick and Rudder Stein Air Grove Aircraft TCW Technologies Dynon Avionics AeroLED MGL Avionics Leading Edge Airfoils Desser EarthX Batteries Garmin G3X Touch
Page 2 of 4 FirstFirst 1234 LastLast
Results 11 to 20 of 34

Thread: engine runs rough

  1. #11
    Senior Member Slyfox's Avatar
    Join Date
    Dec 2008
    Location
    felts field, spokane
    Posts
    1,327

    Default Re: engine runs rough

    like I said I need to find out which side I'm working on, a or b. I know which side is which on the diagram not on my plane yet. going to rip the system off the motor mount and dig in maybe tonight. I was way excited that it turned from an intermittent problem to a hard problem. I'm sure I'll find it.
    steve
    slyfox
    model IV 1200-flying
    912uls
    IVO medium in-flight
    RV7A-flying
    IO-360
    constant speed prop

  2. #12
    Senior Member Slyfox's Avatar
    Join Date
    Dec 2008
    Location
    felts field, spokane
    Posts
    1,327

    Default Re: engine runs rough

    well it tested positive for a bad coil. I ordered one and I hope this is the end to this saga.
    steve
    slyfox
    model IV 1200-flying
    912uls
    IVO medium in-flight
    RV7A-flying
    IO-360
    constant speed prop

  3. #13

    Default Re: engine runs rough

    Great to hear you’ve isolated the issue. Keep us informed when the new coil goes in if the problem is solved!

  4. #14
    Senior Member Slyfox's Avatar
    Join Date
    Dec 2008
    Location
    felts field, spokane
    Posts
    1,327

    Default Re: engine runs rough

    the saga continues. I did put that coil on, didn't fix it. I got me a timing light and put it on t1 and it wasn't firing. checked t-2 and it was firing. what the heck. that's on the same coil. can't be the trigger it runs both on or should I say fires the coil with one trigger for t1 and t2(let me know if I'm wrong) . so back to the cdi module. this is the new one I got about a year ago with soft start. my thinking is this thing is bad. so what I'm going to do now is take the module I took out and put it in the freeze for an hour and put it on ice and take it to the airport and install it and hopefully be able to start the plane. you see it failed and wouldn't work until the engine has 2000 rpm. it is said it will start working if put on ice for a bit. this is a green label cdi. I will see if it will start and have the timing light on that plug. got me baffled for sure. I did check the ohms for the triggers, they are all the same so should have good wires going down to the triggers. wish me luck, cus that is what this is turning into.
    steve
    slyfox
    model IV 1200-flying
    912uls
    IVO medium in-flight
    RV7A-flying
    IO-360
    constant speed prop

  5. #15

    Default Re: engine runs rough

    sorry to hear the frustrations continue. It’s odd as a single coil is triggered by a single trigger wire from the cdi. If one of the plugs on that coil is firing, the trigger from the cdi is good. Have you changed out the spark wire and plug boot to see if those have an internal short? Napa auto parts will have some 7mm wire you can pick up for a few buck to make a test wire.

  6. #16
    Senior Member Slyfox's Avatar
    Join Date
    Dec 2008
    Location
    felts field, spokane
    Posts
    1,327

    Default Re: engine runs rough

    it now has a new coil for that t1 t2, came with new secondary wire and I bought new end caps. I did change to the other plug in for the triggers and that made that t1 fire on the timing light. if it is in the cdi it will be a total weird happening, things like that happen to me. lol anyway I'm going to try and install the old cdi and see if it will fire with things hooked up normal for the A circuit. Hope that does good. I'm not going to buy another cdi, they lost me on that one. factory anyway.
    steve
    slyfox
    model IV 1200-flying
    912uls
    IVO medium in-flight
    RV7A-flying
    IO-360
    constant speed prop

  7. #17

    Join Date
    Jan 2010
    Location
    scotland
    Posts
    33

    Default Re: engine runs rough

    Check your connections too each plug cap! Found one that was not into the centre wire and caused a right huntdown, symptoms as you had

  8. #18
    Senior Member Slyfox's Avatar
    Join Date
    Dec 2008
    Location
    felts field, spokane
    Posts
    1,327

    Default Re: engine runs rough

    update:
    I replaced the spark plug in no. 1 top. I now have a running engine. I cleaned the plugs as they were black from ground runs. starts nice and flew for an hour in the pattern. I have a slight vibration from 3400rpm on down, idles just fine. Not sure if this is normal or not, the cowl will vibrate at the front section when it does it. plenty of power. I've done everything you can think of on this thing. the idle circuit set screw was set a 1/2 turn out and I increased it to 1 after landing. I didn't want to pull the choke for that has fouled the plugs in the past, but if I need to I will the next time I fly. there was no fall out of cylinders on climb out at all, just running with a little vibration under 3400rpm. what to do, not sure. on a mag check at 4000rpm on the ground, both are equal. with a drop of about 150 or less.
    steve
    slyfox
    model IV 1200-flying
    912uls
    IVO medium in-flight
    RV7A-flying
    IO-360
    constant speed prop

  9. #19

    Join Date
    Mar 2010
    Location
    TX
    Posts
    112

    Default Re: engine runs rough

    Model IV with 912 ULS with 540 hours. I've always had a little vibration in the 3000-3500 RPM range. Is your vibration at 3400 RPM new? I have been led to believe that mine is due to harmonics in that range. I had a dynamic balance done right after I completed phase I and it is smooth from 2000 RPM to about 3000 RPM and over 3500.

    Henry

  10. #20
    Senior Member Slyfox's Avatar
    Join Date
    Dec 2008
    Location
    felts field, spokane
    Posts
    1,327

    Default Re: engine runs rough

    Quote Originally Posted by henrysamson View Post
    Model IV with 912 ULS with 540 hours. I've always had a little vibration in the 3000-3500 RPM range. Is your vibration at 3400 RPM new? I have been led to believe that mine is due to harmonics in that range. I had a dynamic balance done right after I completed phase I and it is smooth from 2000 RPM to about 3000 RPM and over 3500.

    Henry
    I'm going to say it's newer. I've also had vibration at that speed you mentioned, but this seems a little bit more pronounced and goes down a little lower.
    steve
    slyfox
    model IV 1200-flying
    912uls
    IVO medium in-flight
    RV7A-flying
    IO-360
    constant speed prop

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •